读取ppm或pgm文件

好的，您可以使用以下代码读取ppm或pgm文件：

def read_pgm_file(filename):
    with open(filename, 'rb') as f:
        # Read header
        magic_number = f.readline()
        if magic_number != b'P5\n' and magic_number != b'P2\n':
            raise ValueError('Invalid magic number: {}'.format(magic_number))

        comment = f.readline()
        while comment.startswith(b'#'):
            comment = f.readline()

        width, height = map(int, comment.split())

        max_val = int(f.readline().strip())

        # Read image data
        if magic_number == b'P5\n':
            img = np.fromfile(f, dtype=np.uint8, count=width*height).reshape((height, width))
        else:
            img = np.zeros((height, width), dtype=np.uint8)
            for i in range(height):
                row = f.readline().split()
                for j in range(width):
                    img[i, j] = int(row[j])

        return img

def read_ppm_file(filename):
    with open(filename, 'rb') as f:
        # Read header
        magic_number = f.readline()
        if magic_number != b'P6\n' and magic_number != b'P3\n':
            raise ValueError('Invalid magic number: {}'.format(magic_number))

        comment = f.readline()
        while comment.startswith(b'#'):
            comment = f.readline()

        width, height = map(int, comment.split())

        max_val = int(f.readline().strip())

        # Read image data
        if magic_number == b'P6\n':
            img = np.fromfile(f, dtype=np.uint8, count=3*width*height).reshape((height, width, 3))
        else:
            img = np.zeros((height, width, 3), dtype=np.uint8)
            for i in range(height):
                row = f.readline().split()
                for j in range(width):
                    img[i, j, :] = [int(row[j*3+0]), int(row[j*3+1]), int(row[j*3+2])]

        return img

这段代码使用numpy库以二进制格式读取ppm或pgm文件，并将其转换为numpy数组。其中，`read_pgm_file()`函数用于读取pgm文件，`read_ppm_file()`函数用于读取ppm文件。